GB1473732A - Methods and devices for monitoring the state of a gear box - Google Patents

Abstract

1473732 Change speed control AUTOMOBILES M BERLIET 31 July 1974 [6 Aug 1973] 33704/74 Heading F2D The position of movable members such as sliding selector rods 101, 102 controlling forward ratios, reverse and neutral in a motor vehicle transmission, is recorded at any instant by a binary logic counting code in which each possible condition of the transmission is associated with an element of a binary coding standard, all the elements of which have the same number of bits, each bit being defined by a detector which co-operates with each of the said movable members. This reduces the number of detectors, such as electrical contacts, hydraulic, pneumatic (e.g. logic), optical or electronic devices, in comparison with the usual limit switches for positional indication. The principle for two rods 101, 102 is shown in Fig. 1. A transverse bar 109, pivoted on a fixed axis 111, overlies both rods 101, 102 each of which has two notches 105 ... 108 which, when aligned, allow the bar 109 to fall and emit a "0" signal, whilst when the notches are disaligned, as shown, the bar is raised by the surface of one of the rods and emits a "1" signal. The device may be applied to transmissions having in addition to neutral and reverse, five, six, eight, fourteen, thirty or any other number of forward ratios. In a six ratio and reverse control, Fig. 3, three bits, comprising microswitches a, b, c, are controlled by three transverse bars 109, 209, 309 overlying four three-position selector rods I ... IV, notched as shown. The binary code is as follows. In neutral all the bars 109 &c. are down, emitting signals "000" at the microswitches abc. In first ratio, with the selector rod I moved right, the rod 309 alone is raised, signalling "001"; in second (II left), 209 alone is raised giving "010"; in third (II right) two bars 209, 309 are raised giving "011"; similarly fourth gives "100"; fifth "101"; sixth "110" and reverse "111". In Fig. 4, not shown, four transverse bars 109 ... (409), overly eight selector rods controlling fourteen forward ratios and one reverse. The system separates the detectors, such as microswitches from the mechanical components, and may be applied to existing transmissions by replacing the casing and appropriately notching the selector rods.